Frequency-stabilized power source for a.c. driven motors comprising signals from a selected tone generator amplified to required power-voltage level



Feb. 3, 1970 MAKI YAMASHITA 3,493,666

FREQUENCY-STABILIZED POWER SOURCE FOR A.C. DRIVEN MOTORS COMPRISING SIGNALS FROM A SELECTED TONE GENERATOR AMPLIFIED TO REQUIRED POWER-VOLTAGE LEVEL Filed May 8, 1968 2 Sheets-Sheet l INVENTOR. m. Ymn-sw (v-n Feb. 3, 1970 MAKI YAMASHITA 3,493,666

FREQUENCY-STABILIZED POWER SOURCE FOR A.C. DRIVEN MOTORS COMPRISING SIGNALS FROM A SELECTED TONE GENERATOR AMPLIFIED TO REQUIRED POWER-VOLTAGE LEVEL Filed May 8, 1968 2 Sheets-Sheet 2 FIG. 2-

ITONE GENERATOR 2 AMPLIFIER 5 TAPE RE DER GROUP COR TONE GENERATOR F I G 3 GROUP I i 4 SELECTION SWITCH 5 TAPE RECORDER 2\ AMPLIFIER United States Patent FREQUENCY-STABILIZED POWER SOURCE FOR A.C. DRIVEN MOTORS COMPRISING SIGNALS FROM A SELECTED TONE GENERATOR AMPLI- FIED TO REQUIRED POWER-VOLTAGE LEVEL Maki Yamashita, Hamamatsu-shi, Japan, assignor to Nippon Gakk Seizo Kabushiki Kaisha, Hamamatsu-shi,

Shizuoka-ken, Japan, a joint-stock company of Japan Filed May 8, 1968, Ser. No. 727,646 Claims priority application Japan, May 11, 1967 (utility model), 42/38,814 Int. Cl. Gllb 31/02 US. Cl. 841.02 4 Claims ABSTRACT OF THE DISCLOSURE In an electronic musical instrument, tone signals out of tone generators are amplified up to power voltage to be available as power supply for A.C. driven motors. The output signals of some of tone generators are selectively supplied by a selector switch to a power amplifier leading to a power service outlet, from which frequency-stabilized power at frequencies selectable over a wide range can be obtained for a broad range of uses, one of which is to drive the motor of a tape recorder incorporated in an electronic musical instrument.

BACKGROUND OF THE INVENTION This invention relates generally to the field of electronic musical instruments, to the field of electric power supplying devices, and to the field of magnetic sound recordingreproducing means (hereinafter referred to as a tape recorder) More specifically, the invention concerns a new device for supplying frequency-stabilized electric power in an electronic musical instrument.

Heretofore, while it has been known that the frequency accuracy and stability of tone generators of electronic musical instruments are great (for example, errors Within 2 percent, there has apparently been no attempt to utilize this great accuracy and stability for other purposes and applications, particularly for driving A.C. motors of equipments whose speed is required to be accurate and stable, by the frequency-stabilized power derived from the tone signal being amplified up to power voltage.

SUMMARY OF THE INVENTION It is an object of the invention to utilize this great stability of frequencies to provide a device for supplying frequency-stabilized electrical power in an electronic musical instrument.

According to the present invention, briefly summarized, there is provided a frequency-stabilized power supply device in an electronic musical instrument characterized by the combination of a plurality of tone generators, a power amplifier, and a service outlet connected through the power amplifier to the output side of the tone generator.

According to the invention, in another aspect thereof, there is provided a device of the above described character for an electronic musical instrument provided with a tape recorder having a motor, which is connected through the power amplifier to the output side of the tone generator.

The nature, details, and utility of the invention will be more clearly apparent from the following detailed description with respect to preferred embodiments of the invention, when read in conjunction with the accompanying drawing, in which like parts are designated by like reference numerals and characters.

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BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a schematic diagram showing the essential arrangement of one example of a frequency-stabilized power supply device embodying the invention;

FIG. 2 is a block diagram showing another embodiment of the invention as applied to an electronic musical instrument provided with a tape recorder;

FIG. 3 is a schematic diagram showing a more specific example of the application indicated in FIG. 2.

DETAILED DESCRIPTION ON PREFERRED EMBODIMENT In one preferred embodiment of the invention as illustrated in FIG. 1, the electronic musical instrument provided With a device for supplying frequency-stabilized power has a tone generator group 1 with output sides to one of which a service outlet (or receptacle) 3 is connected through a power amplifier 2.

The tone generator group 1 comprises, first in the case of a frequency-divider system, twelve master oscillators each followed by a clipper and a chain of frequency dividers; and second in the case of an individual-note system, at least one separate and individually tuned oscillator for each desired pitch. In either system, the tone generator group 1 is made up of tone generators in accordance with the number of tones required for the musical instrument.

The tone generators Which are, according to this invention, available for commercial A-C equipments would be in the range of from G to B the oscillation frequencies of which are G 48,999 Hz., Gi 51,913 Hz., A 55,000 Hz., All, 58,270 Hz., and B 61,735 Hz., and the output from one tone generator among these generators is used at a time.

The tone generator group 1 and the power amplifier 2 are connected through a selector switch 4 interposed therebetween for switching at will. The switch 4 is a multiple-contact switch having single movable contact and a plurality of stationary contacts of a number corresponding to the number of generators to be utilized within the tone generator group 1. The service outlet 3 to which the power-amplified generator signal is to be supplied is mounted at a position convenient for use, for example, on the rear face of the amplifier chassis or a suitable position on the console of the electronic musical instrument.

The power amplifier 2 is so constructed that its output voltage is volts (or 117 volts in US.) for convenience in practical use. When the intended driven motor is of a low voltage type, the output power voltage may be as low.

Since a service outlet 3 is thus connected through the power amplifier 2 to the output side of a tone generator of the group 1 in the musical instrument according to the invention, an A.C. electric power of stable frequency is obtained, and the range of utility thereof is thereby wide. This feature is advantageous in that, by utilizing this arrangement for an equipment requiring a high degree of frequency stability as, for example, an equipment in which a synchronous motor is used, the detrimental elfects of errors due to frequency variation are almost completely eliminated.

Furthermore, by utilizing a plurality of tone generators through a multiple-contact selector switch, great convenience is afforded for devices such as the power supply for a tape recorder.

In a fundamental example of practice of the present invention as illustrated in FIG. 2, a magnetic sound recording and reproducing device (hereinafter referred to as a tape recorder) 5 is installed within the electronic musical instrument of the invention, and the output side of the tone generator group 1 is connected through the power amplifier 2 to the motor M of the tape recorder 5.

Accordingly, the rotation of the motor M is stable. Thus, the tape recorder 5 can be used, of course, in the ordinary manner, and, in addition, when the tape recorder is used in conjunction with the electronic musical instrument, special acoustical effects can be obtained. Furthermore, even when there is a deviation in the pitches of the tone generators between recording and reproduction, the tape speed deviates in the same manner. Therefore, at the time of reproduction, the pitches of the reproduced sounds and those of the played tones on that musical instrument will be same and in tune.

In a further example of practice of the invention as illustrated in FIG. 3, a tape recorder 5 is installed within the electronic musical instrument, and the movable contact of a multiple-contact selector switch 4, such as the aforedescribed switch 4, is connected through the power amplifier 2 to the motor M of the tape recorder 5. Output terminals of ditferent frequencies of a tone generator group 1 are connected respectively to the stationary contacts of the switch 4, as in the aforedescribed example. Accordingly, a plurality of different generators can be utilized.

Tone generators in an electronic musical instrument are provided for each of the chromatic tones, and there exist a tone higher by one octave than a certain tone and a tone lower by one octave than said tone. Accordingly, by operating the switch 4, the rotation of the tape recorder can be selected as desired.

For example, the motor M is driven by the power out of A at the time of recording and it is driven by the power out of A# at the time of reproduction, which means reproduction can be accomplished at the pitch which is exactly one semitone above that at the time of recording, thus enabling the modulation of the music. In addition, there are afforded further practical advantages such as the possibility of changing the tape speed of the same driving means of a tape recorder, such as, for example, at 19 cm./s., 9.5 cm./s., and 4.75 cm./s., when A A and A are selectively utilized by switching therebetween.

It should be understood, of course, that the foregoing disclosure relates to only preferred embodiments of the invention and that it is intended to cover all changes and modifications of the examples of the invention wherein chosen for the purposes of the disclosures, which do not constitute departures from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. A device for supplying frequency-stabilized electrical power in an electronic musical instrument comprising; tone generators each having an output side, a power amplifier, and a service outlet connected through the power amplifier to the output side of one of said tone generators.

2. A device for supplying frequency-stabilized electrical power in an electronic musical instrument comprising; a plurality of tone generators with respective output terminals, a selector switch having a plurality of stationary contacts connected respectively to said output terminals and a movable contact for selectively contacting the stationary contacts, a power amplifier, and a service outlet connected through the power amplifier to said movable contact of said selector switch.

3. A device for supplying frequency-stabilized electrical power in an electronic musical instrument provided therein with a magnetic sound recorder-reproducer having an electric motor, said device comprising a power amplifier and tone generators each having an output side one of which is connected through the power amplifier to said motor.

4. A device for supplying frequency-stabilized electrical power in an electronic musical instrument provided therein with a magnetic sound recorder-reproducer having an electric motor, said device comprising a plurality of tone generators with respective output terminals, a selector switch having a plurality of stationary contacts connected respectively to said output terminals and a movable contact for selectively contacting the stationary contacts, and a power amplifier, said movable contact being connected through the power amplifier to said motor.

References Cited UNITED STATES PATENTS 2/1953 Luberoif.

6/1969 Camras US Cl. X.R. l .9-100.2 

